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D1 Host and Defense > Antimicrobials 1 -Smith > Flashcards

Antimicrobials 1 -Smith Flashcards

1
Q

describe the characteristics of gram (+) cells and antibiotics?

A

-have a cell wall composed of thick peptidoglycan layer which this is the target of many antimicrobials

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2
Q

describe the characteristics of gram (-) cells and antibiotics?

A
  • have a thin peptidoglycan cell wall and they have an LPS cell membrane outside
  • the penicillin binding proteins are hard to target with antimicrobials b/c of the cell membrane
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3
Q

what the the structure of B lactam antimicrobials?

A

double ring

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4
Q

how do B lactam antimicrobials work?

A
  • they resemble D- Alanine end of the peptide that serves as a substrate for transaminopeptidase enzymes
  • essentially B-lactam’s are inserted into the cell wall
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5
Q

the be effective B lactam’s must be what 4 things?

A
  1. evade bacterial defenses
  2. penetrate outer cell layers to inner cytoplasmic membrane
  3. keeps it’s B lactam ring intact
  4. bind to transpeptidase (penicillin binding protein- PBP)
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6
Q

what do gram (+) organisms have outside the cell wall that can inactivate penicillin?

A

penicillinases (B lactamases)

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7
Q

what are transpeptidase enzymes and what is their function?

A

-they crosslink adjacent glycan chains by removing the terminal D-alanine residue

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8
Q

how B lactams

A

B-lactams bind to the active site of penicillin binding protein and prevent transpeptidation. The bacteria than can not make new peptidoglycan autolyses.

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9
Q

B-lactam drugs are only effective on what type of organisms?

-they are inactive against?

A
  • rapidly dividing organisms

- inactive against: fungi, viruses, mycobacteria (organisms without a peptidoglycan later)

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10
Q

what are the 5 types of B lactam antimicrobials?

A
  1. natural penicillins
  2. aminopenicillins = “extended spectrum penicillins”
  3. Penicullinase-resistant penicillins = “antistaphylococcal penicullin)
  4. Anti pseudomonal penicillins
  5. Cephalosporins
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11
Q

what are the types of Natural Penicillins?

A
  1. Penicillin G

2. Penicillin VK

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12
Q

What is the mechanism of Natural penicillins

A
  • Inhibits transpeptidase (penicillin-binding protein)

- Activates autolytic enzymes

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13
Q

are Natural penicillins bacteriostatic or bacteriocidal?

A

bacteriocidal

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14
Q

effect of penicillinase onNatural penicillins ?

A

-they are sensitive to penicillinase (B lactamases)

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15
Q

Natural Penicillins are used to clinically treat what?

A

Streptococci, penumococci, enterococci (w aminoglycosides) miningococci, treponema palladium

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16
Q

Natural Penicillins are effective against what type of organisms?

A

gram + cocci and less on gram (-) except nisseria species

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17
Q

Toxicity of Natural Penicillins?

A

hypersensativity reactions

-hemolytic anemia

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18
Q

what are the penicillinase-resistant penicillins?

A
  • methicillin
  • Nafcillin
  • oxacillin
  • dicloxacillin
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19
Q

what is the mechanism of penicillinase-resistant penicillins?

A
  • Inhibits transpeptidase (penicillin-binding protein)
  • Activates autolytic enzymes
  • bacteriocidal
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20
Q

what are the 3 Beta-lactamase inhibitors?

A
  1. clavulanate
  2. sublactam
  3. tazobactam
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21
Q

what is unasyn?

A

ampicillin + sublactam

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22
Q

what is the spectrum of penicillin?

A

narrow spectrum

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23
Q

non MRSA Staphylococcal infections are treated with what?

A

-Naficillin - “Naf for Staph” - this is a penicillinase resistant penicillin

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24
Q

What are examples of Aminopenicillins?

A
  • ampicillin

- axomicillin

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25
Q

mechanism of Aminopenicillins?

A
  • Inhibits transpeptidase (penicillin-binding protein)
  • Activates autolytic enzymes
  • bacteriocidal
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26
Q

spectrum of Aminopenicillins?

A

-wide spectrum when combined with clavulanic acid

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27
Q

effect of B lactamase on Aminopenicillins ?

A

penicillinase sensitive - paired w clavulanic acid to inhibit this effects

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28
Q

what type of organisms are Aminopenicillins effective against?

A

gram + bacteria and gram (-) rods

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29
Q

what is the drug of choice for prophylaxis of infective endocarditis?

A

amoxicillin (Aminopenicillin) or cephalexin if allergic

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30
Q

what is the drug of choice for Listeria monocytogenes and enterococci?

A

Aminopenicillins

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31
Q

what is a toxicity risk of Aminopenicillins?

A

pseudomembranous colitis

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32
Q

how does probenecid effect the clearance of Ampicillin?

A

probenecid slows renal excretion of Ampicillin

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33
Q

what is the mnemonic for Ampicillin?

A

‘AMPing up AMO HELPS kill a wide spectrum of enterococci’

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34
Q

what can inactivate ampicillin when mixed in IV solutions?

A

hydrocortisone

35
Q

what are the Anti-pseudomonal Penicillins

A 
Anti-pseudomonal Penicillins
-Ticarcillin 
-Carbenicillin 
-Piperacillin
TCP: Takes Care of Pseudomonas
36
Q

mechanism of Anti-pseudomonal Penicillins and spectrum of activity?

A
  • Inhibits transpeptidase (penicillin-binding protein)
  • Activates autolytic enzymes
  • bacteriocidal
  • extended spectrum
37
Q

is Anti-pseudomonal Penicillins sensitive to penciillinase?

A

-yes penicillinase sensitive

38
Q

Anti-pseudomonal Penicillins are used to treat what?

A

pseudomonas and gram (-) rods

-synergistic with aminoglycosides

39
Q

what is the broadest spectrum penicillin?

A

piperacillin

40
Q

how are cephalosporins excreted?

A

renally excreted

41
Q

what are the 1st generation cephalosporins?

A

Cefazolin (IV), Cephalexin

oral

42
Q

what do the 1st generation cephalosporins treat?
When are they typically used?
Mnemonic:

A 
-Gram (+): also some Gram (-)
Proteus mirabilis
E. coli
Klebsiella pneumonia
-typically used before surgery
Mnemonic: 1st Generation for a PEcK
43
Q

what are the second generation cephalosporins?

A

Cefoxitin
Cefaclor
Cefuroxime

44
Q

what do the second generation cephalosporins treat?

A

2nd Gnereration for a HEN PEcK —gram (-)

  • Haemophilus Influenza
  • Enterobacter aerogenes
  • Neisseria
  • Proteus mirabilis
  • E. coli
  • Klebsiella pneumonia
45
Q

how does penicillinase effect cephalosporins?

A

cephalosporins = penicillinase resistant

46
Q

what are the 3rd generation cephalosporins?

A

Ceftriaxone,
Cefotaxime,
Ceftazidime,
cefdinir

47
Q

what do the 3rd generation cephalosporin’s treat?
that type of organisms?
mnemonic?

A

3rd Generation crosses BBB
-Gram positive and gram-negative cocci and gram
negative bacilli,
-treats :Meningitis, anaerobes, and gonococci, pseudomonas
-Mnemonic: Tri to TAX TAZ! (3rd Generation). Third generation individual drugs Pseudomonas (ceftazidine), anaerobes (ceftozoxime), and gonococci (ceftriaxone)

48
Q

What are examples of 4th generation cephalosporins?

A

Cefepime

49
Q

What do 4th generation cephalosporins treat?

A

4th Generation Pseudomonas

50
Q

what are examples of 5th generation cephalosporins?

A

ceftaroline

51
Q

what can 5th generation cephalosporins be used to treat?

A

MRSA

52
Q

toxicity risk of cephalosporins

A
  • hypersensitivity rxns to increasing toxicity of aminoglycosides
  • pseudomembranous colitis
53
Q

what is the mechanism of Aztreonam?

A
  • Inhibits transpeptidase (penicillin-binding protein)
  • Activates autolytic enzymes
  • bacteriocidal
54
Q

are Aztreonam Penicillins sensitive to penciillinase?

A

B lactamase resistant

55
Q

Aztreonam is effective against what type of organisms?

A

gram negative aerobic rods
Mnemonic: Aztreonam treats a SPiKe
-Serratia, Pseudomonas, klebsiella

56
Q

what is the risk of toxicity of Aztreonam?

A

pseudomonas colitis - overgrowth of C. difficile

57
Q

when should Aztreonam be used?

A

Use with ‘penicillin-allergic’ patients and those with renal

insufficiency who cannot tolerate

58
Q

what can be done to increase the coverage of Aztreonam?

A

pair it with Vancomycin or clindamycin

59
Q

what are the carbapenems?

A
  • imipenem
  • meropenem
  • ertapenem
60
Q

what is the mechanism of carbapenems?

A
  • Inhibits transpeptidase (penicillin-binding protien)
  • Activates autolytic enzymes
  • bacteriocidal
61
Q

are carbapenems sensitive to penicillinase?

A

-penicillinase resistant ( b lackam resistant)

62
Q

what is the drug of choice for enterobacteria?

A

Carbapenems

63
Q

What is the risk of toxicity for carbapenems?

A

CNS toxicity

64
Q

Imipenem (carbapenem) must be paired with _______ and why?

A

imipenum must be paired with cilistatin (an inhibitor of renal dihydropeptidase1) to decrease inactivation in renal tubules

65
Q

how are carbapenems excreted?

A

renally excreted

66
Q

what is the broadest antibacterial available?

A

imipenum + cilistatin

67
Q

carbapenems are effective against what type of organisms?

A

gram positive cocci
gram negative rods
anaerobes

68
Q

mechanism of vancomycin?

A

Inhibits cell wall formation by binding D-ala, D- ala portions of cell wall precursors

69
Q

what is vancomycin used to treat?

A

treats multidrug resistant gram (+): Staphylococcus aureus and Clostridium difficile

70
Q

what is the risk of toxicity of vancomycin?

A

Nephrotoxicity, Ototoxicity, Thrombophlebitis, Flushing ‘red man syndrome’
Mnemonic: The Red Man will NOT take Vanco

71
Q

what is the mechanism of Bacitracin?

A

Blocks peptidoglycan synthesis

72
Q

what is the risk of toxicity of Bacitracin?

A

Nephrotoxicity Ototoxicity

73
Q

what is the mechanism of Daptomycin

A

Inserts into cell membrane, forming ion channels that disrupt ionic concentration gradient of bacteria (BACTERICIDAL)

74
Q

Daptomycin is used to treat what?

A

Vancomycin- and methicillin-resistant Gram (+) bacteria

75
Q

how does amoxicillin effect methotrexate?

A

amoxicillin dose dependently inhibits renal tubular secretion of methotrexate = high serum levels

76
Q

how is ampicillin administered?

A

parenterally (IV)

77
Q

Aminopenicillins treat what bugs?

A

H. influenza, enterics like E. coli, Salmonella, Shigella

78
Q

what are the anti staphylococcal penicillins?

A

Methicillin, nafcillin, oxacillin, dicloxacillin

79
Q

what happens as the generation of cephalosporins goes from 1 to 5?

A

the gram positive activity decreases and it becomes more resistant to B-lactamase enzymes

80
Q

what type of cephalosporins do superinfections occur in and why?

A

–more likely in 2nd, 3rd, and 4th generation cephalosporins b/c they have reduced gram positive activity (particularly against enterococci)

81
Q

what is the first drug of choice for surgical prophylaxis?

A

cefazolin - a 1st generation cephalosporin

82
Q

are Cephalosporins penacillinase resistant??

A

yes Cephalosporins are resistant to penicillinase enzymes

83
Q

B lactamase resistant antibiotics?

A
  • penicillinase resistant penicillins( methicillin, nafacillin…etc
  • cephalosporins
  • azetreonam
  • carbapenems

D1 Host and Defense (5 decks)

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